If you want to stay with Suzuki gear box, find a '04 and later XL7 gear box. Suzuki up graded them with larger shafts, and they should hold up. They were pushing 185 hp through them. I suggest going to the ford, because of the ease of mating them, and if going to automatics the compatibility of the computers. The '04 and later XL7's ran 3 main computers and a couple auxiliary ones, that have to communicate with each other or they throw codes.
Blending computer systems is a tedious task. The benefits are for those who do it.